scribner



(No Mod'l.)

3 Sheets-Shet 1.

0. E. SORIBNER. TELEPHONE EXCHANGE SYSTEM.

Patented May 15, 1888.

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(No Model.) 3 Sheets-Sheet 2. C. E. SGRIBNER.

TELEPHONE EXCHANGE SYSTEM. N0.'383,013. Patented May 15, 1888,

, fl mw (No Model.) 0 E. SGIRIBNER. s Sheets-Sheet 3.

TELEPHONE EXCHANGE SYSTEM. No. 388,013. Patented May 15, 1888.

THE NORRIS PEI-Ens co.. musmmmm, u c

ing a part of this specification.

employed.

UNITED STATES PATENT. OFFICE.

CHARLES E. SCRII BNER, OF CHICAGO, ILLINOIS, A SSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

TELEPHON E-EXCH ANGE SYSTEM.

" SPECIFICATION forming part of Letters Patent No. 383,013, dated May 15, 1888.

Application fllcd March 5, 1893. I

' nois, have invented a certain new and useful Improvement in Telephone Exchange Systerns, (Case 47 of which the following is a full, clear', concise, and exact description, reference being had to the accompanying drawings, form- My invention is designed for use in connection with a system of telephone-exchange in which complete metallic telephone-circuits are Complete metallic circuits havebeen used heretoforein large cities,and doublepointed connecting-plugs have been provided at the central office for the purpose of uniting into one circuit the complete metallic circuits of two subscribers.

My invention, as herein described, consists in new switching apparatus and circuits for the subscribers outfit, by means of which a subscriber who desires to talk to the central oifice may ground his metallic circuit through his telephone and connect the two wires with the listening operator as a single ground-circuit.

My invention also consists in'improvements in the spring-jack used upon the switch-board and in the apparatus for receiving and transmitting signals at the central office.

In the accompanying drawings, which are illustrative of my invention, Figure lis adiagram of the circuits between the central office and the subscribers stations. Fig. 2 is a partial sectional view showing the doublepointed or. loop plug and my improved spring-jack. Fig. 3 is an enlarged view showing certain parts of the central-office apparatus in detail. Fig. 4 is a detailed view of the calling-battery switching apparatus. Fig. 5 is a detailed view of the commutator and other apparatus at a subscribers station with the circuits extending to the subscribers station from the central oflice.

Like parts are indicated by similar lfiters of reference throughout the ditferent figures.

The subscribers S, S, and S are each provided with a metallic circuit. Thelocal circuit of the microphone and-primary of induction-coil may be provideclat each station, in

Serial naszo'tt. (No model.)

the usual manner. Each subscriber is moreover provided with a telephone, a switch, a signal-bell, and circuit-changing keynor commutator.

At station S the telephone a is shown hanging on the lever b of the telephone-switch,.and the bell c is directly in circuit. When the switch-lever is changed to its other position, as shown at S, the shunt d of the bell is closed and the shunt e of the telephone is opened. When the switch is in this position and the commutator in its normal position, the-telephone receiver and transmitter are included directly in themetallic circuit. The circuit at station S may be traced from one line of the metallic circuit through the telephone transmitter and receiver to the upper spring of the commutator to the contact-point upon which said spring-rests, and thence to the switch-lever, and thence, by contact-point and shunt-wire d, to the other part of the metallic circuit. The transmitter and receiver are thus included directly in the metallic circuit, as shown at'said station 8*.

At station S the commutator f is shown pressed in, so as to ground the two lines 9 h of the metallic circuit through the telephone. This circuit may be traced as follows: From the ground-line t to the lever k of the commutator, thence byline I through the telephone and secondary of the induction-coil to m. From m we have a single circuit in two branches to the contact-point of the spring-jack at the central office-one branch directly, the other branch by line n to the spring 0 of the'commutator, thence by line 1) to point q, and thence by the other wire, h, of the metallic circuit to the spring-jack.

I will now describe my improved springjack as shown in detail in Fig. 2. The tubular frame 1 is provided with a contact-point, s. The spring or lever t is insulated from the frame'r at one end and adapted to make contact with the frame at the other end. The wire 9 is connected directly to the spring t and thence to the insulated contact-point s. The

wire h is connected to the frame and thence to the spring and the said contact-point s.

Referring now to Fig. 1, it will be seen that we have a single circuit composed ,of branch wires g and h from station S direct to point a ICO phone. Thus the springjack switch at the right in Fig. 1 is shown with its spring or lever resting upon its ground-contact .s. The metallic circuitg h ofstation S is thus connected with the ground branch,which includes the operators telephone-outfit.

Suppose subscriber S wishes to talk with the central otfice. By pressing in the knob of commutatorf, as shown, a branch circuit will be formed, asshown at station S", from the metallic circuit through the telephone to ground at said station. The subscriber S is thus brought into communication with the listening operator at the central oflice, the

metallic circuit formed by wiresg hbeing connected througha branch circuit to ground at station S, the subscribers telephone being in said-branch,and at thccentral office through the branch containing the listeningoperators telephone, as shown.

The ground branch at the subscribers station may be traced from the junction at through the induction-coil of the transmitter to the telephone, and by wire l to spring is of the commutator, and thence by 'wire i to ground.

When the telephone a is on the switch b, as shown at station S, the hell 0 will be in the metallic circuit, while the telephone will be shunted. 0n removing the telephone from the switch the position of the switch changes and the telephone is brought into the metallic circuit, while the bell is shunted, as shown at station S The bell and telephone at any subscribers station may thus be brought alternatively into and out of the metallic circuit by changing the position of the telephoneswitch at the'said station. -I have thus described a circuit between the subscriber and t he'listening operator.

The metallic circuits of two subscribers, as Sand S, may be united by means ofa pair of double-pointed or loop plugs and conducting- -cords. The double-pointed plug is shown in detail in Fig.2 and is essentially the same as the double-pointed plug shown in my Letters PatentNo. 262,701, dated August 16, 1882. When this plug is inserted in my improved spring-- jack,the springislifted from the contact-point s and also from contact'with the frame of the said spring-jack. 'Wirey is thus disconnected from the frameand connected to the central point of the plug, while at the same time wire h is connected to the outer point or collar of the plug. One wire of the metallic circuit may thus be connected to one strand of the conducting-cord and the other wireto the other strand.

At station S, Fig. 1, the telephone is shownremoved from the switch and included directly in the metallic circuit, as before described. This circuit at station S maybe traced, beginning at the spring of the spring-jack at the central office, thence through the transmitter and receiving-telephone to the upper spring otthe commutator at said station, thence to the point on which said spring rests, thence to the telephoneswitch, and thenceby the shunt-wire (2 around the bell to the, other portion of the metallic circuit. The telephone at station S is thus included directly in the metallic circuit, and there is no branch circuit closed to ground, as shown at station S At station 15 (for detail see Fig. 5) the position of the commutator is changed. This change in the position of the commutator is effected by simply pressing upon the knob or keyf. The upper spring, k, of the-commutator is thus separated from its normal contact-point and closed to,the groundlinez, as before described.

I arrange the plugs in pairs and connect the conducting-cords with switching apparatus and a clearing-out annunciator.v I also provide a calling-battery and a listening-out telephone, either of which may be looped into the metallic circuit of two connected subscribers. The calling-battery t is shown in the drawings looped into the metallic circuit of station S.

The battery-plugn consists of two insulated metallic pieces. This plng,when inserted, as shown, between the two springs of the switch,- disconnects the springs from contact-points o w. The battery is thus connected into the circuit of the subscriber called for. and does not find circuit through the line of the subscriber who sent in the call. -On removing the battery-plug the springs of the switch close upon the contact-points v w, and the metallic circuits' of the two subscribers, are united in a single metallic circuit..

The central-ofiice operator may determine whether two subscribers thus connected have ceased talking by looping in the listening-out telephone or. I also provide a clearing-out annunciator, y, so that either of two connected subscribers may send in a signal to disconnect. This annunciator I place in a branch line connected to ground through a battery. This branch line, as shown in the drawings, is con nected to the metallic circuit at the conducting cord of the pair of plugs. ever, be connected to any other part of the circuit with li'lge results. The battery 2 may consist of any number of cells and may be made common to any number of connections, so that a separate clearing-out battery need not be'used for each connectlon'estabiished in the exchange.

Until the lreyf of the commutator of one of two connected subscribers is depressed the battery 2 will remain open. On depressing thekeyf at one oi'the connected stations the circuit of the clearing-out battery 2 will be closed through the anuunciator y, and the shutter will fall, indicating that the subscribers are through talking. 1

ice

It may, howsubscriber may beveonnected into a circuitbranched from the metallic circuit to ground atthe subscribers station. a

3; The united metallic circuits of two subscribers, in combinationw'ith a branch circuit t'o'grouud, including an'anunnciator and battery and switches, whereby either subscriber may ground the metallic circuit,and thereby close the battery and drop the annunciator, substantially as set forth.

4. The combination of a series of metallic circuits-each extending from the central office to a difierentsnbscribers station, and a branch line toground at the central oflice, including the operators telephone, and switches at the central ofiice, one switch included in each metallic circuit, said switches normally connecting their respective metallic circuits with the said branch line.

5. A spring-jack consisting of the frame 1, insulated point .9, and the insulated spring or lever adapted'to make contact with said frame andcontactpoint. p

6. -In a subscribers telephone outfit for metallic-circuit lines, the signal-bell and tele phone, in combination with a branch circuit to ground, and switches and con nections whereby the subscriber may bring the telephone and signal-bell alternately into and out of the linecircuit and may remove the telephone from the line-circuit and connect it into said branch circuit.

7. Aloop-plug, in combination with aswitching device, said switohingdevice being adapted to receive said ioop-plug and having three contact-pieces, said contactpieces being electrically connected in the switching device when the plug is not in it and being electrically disconnected in the switching'device when the plug is in it. w

8. Aloop-plug, in combination with aswitchi ng device, said switching device being adapted to receive said loop-plug and provided with three contact-pieces, two of which are line contact pieces, said contact-pieces being in electric connection with the third contact-piece when the plug is not in the switching device and being electrically disconnected from said third contact-piece when the plug is in the switching device.

9. The combination of a loop-plug with a switching device adapted to receive said loopplug, the switching device having two insulated line-connections and a third insulated connection, and one of said'insulated line-eonnections being normally in electric contact with the other line-connection, and also with said third insulated connection, and being removed from electric contact with said line connection and said third connection when the plug is inserted.

10. The combination of a loop-ph1g with a switching device, the loop-plug having two insulated connections, and the switching device having two insulated line-connections and a' third insulated connection and adapted to receive the loop-plug, one of said line-connections being normally in electric contact with the other. line connection and with said third insulated connection when the plug is not inserted, and when the plug is inserted said lineconnections being disconnected from each other and from said third insulated connec: tion, and each connected with a corresponding insulated connection of the loop-plug.

11. In the central office of a telephone-exchange, two or more switching devices," each of which has two insulated contact-pieces connected to the two terminals of a metallic-circuit telephone line, and athird insulated contact-piece connected with a ground-line common to said switches, and loop'plugs with flexible cords adapted to be placed in and removed from said switching devices, in combination with an operators telephone in said ground line, whereby when a loop'plugis inserted into any switching device the operators telephone is disconnected from the line connected with said switching device, said operator's telephone beingv again automatically connected to said line when the plug is removed.

12. In the central office of a telephone-exchange, a loop-plug with a flexible cord and a switching device adapted to receive said plug, said switching device having two insulated contact-pieces connected to the two terminals of a metallic circuit telephone-line, and also a third insulated contact-piece connected to a ground-line, said third contact-piece being electrically connected with the other contact pieces when the plug is not in the switching device, and being electrically disconnected from said pieces when the plug is in the switching device, in combination with an operators telephonein'said ground-line, whereby when the plug is in the switching device the operators telephone is disconnected from the lineterminals, and when the plug is not in the switching device the operators telephoneis in electrical connection with both o'f said lineterminals.

13. In the central office of a telephone exchange, loop-plugs with two or more switching devices, each of which has two insulated line contact-pieces connected to the two terminals of a metallic circuit telephone-line, and also each provided with a third insulated coutact-piece, which pieces are respectively in electrical connection with said line'contactpieces when a loop-plug is not in the switching device, said third pieces being disconnected from said line contact-pieces when a loop-plug is in the'switching device, and an operators telephone in a ground-line con nected to said third insulated contact-pieces, whereby when a loop-plug is in eitherswitching device the operators telephone is disconnected from both terminals of theline connected thereto, and when the loop-plug is not in the switching device the operators telephone is connected to both terminals of said, line.

14. A suhscribeistelephone-circuit, said circuit extending from the central office to the subscribers otliceand thence back to the central office, a telephone in said circuit at the subscribers office, aswitchlng device by which said telephone may be removed from saidcin cuit and connected iutoa branch circuit, one end'of which is connected to said sn'bscribens circuitand the other end of which is connected withthe ground, in combination with a switching device and an operator-s telephone at the central office, the operators telephone being connected on one side to the ground and on the other side to the switching devioe,the'switch-' ingdevice being connected to the two terminals of the subscribers circuit, whcreby'the subscriber, by operating the switching device at'his'station, may bring his .telephone into circuit with the 'operators telephone,- and whereby the operator, by operating the switching device at the central officc, maydisconnect the subscribers circuitfrom his telcpn one and connect it wilh another subscriber's circult. p

15. The switching device. consisting of a frame provided with -n pl ug-holeoi' considerable depth, a spring or lever, and a third contactpoint, in combination with a loop-plngadaptcd vto lift the spring or lever from the contacthating in the central otilceot' an exchange, in

combination with a branch line at the central office containing-tho operator s telephone,

said branch line being grounded on one side of the telephone, and being normally connected on the other side of the telephone to both terminals of said telephone line, and a switching device, whereby said branch line may be disconnected from the terminals of said telephone-line.

17. The c'ombination'ot' two orniore metallic-circuit telcphonc-lines centering in the central otiice ot a telephone-exchange, with a branch line at the central otlice containing the operators telephone, said branch line be ing grounded on one side of the telephone, and normally connected on-the other side of the telephone with all of said lines, and

switching devices, whereby any of said teie phone-lines may bedisconnecied from said branch line. 18. The combination of two or more metallic-circuit telephone-lines centering in the central oiiice of a telephone-exchange, with a branch line at the central otfice containing the operators telephone, said branch line heing grounded on one side of the telephone, and normally connected on the other side of the telephone with all of said telephone lines, and switching devices, whereby any or said telephone-lines may be disconnected from said branch line, and any two of said telephone lines may be looped together in metallic cir .an operators telephone, in combination with switches, one at each subscriber-7s office, whereby any subscriber may, for conversation with the central office, establish a groundcircuit which shall enrbracehisown'and the operators telephones and part oral'l of his telephone line. -21. In atelcphone exchange, two or more metallic-circuit; telephone-lines, all normally grounded at the central office through an operators telephone, in combination-with switches, one at each subscribers station, wherebyan y subscriber may, for conversation with the centrnlotiice, establish a ground circuit which shall embrace hisownand the operators telephones and part or all of his telephone line, and switching devices at the central oiiice, one for each of said lines, whereby the operator may connect together any two of said lines for exchange communication,

In witness whereof I hereunto subscribe my name this 31st day of August, A. D. 1882.

CHARLES sontsnsa.

Witnesses,

GEo'nenP. BA a'ron, PAUL A S'rannv. 

